Some US residents willing to join terror cells

Congress has been informed that a new national security threat is emerging from home-grown terrorists. Obama administration officials have told Congress that efforts by terrorists to recruit US residents have been working and "domestic radicalisation" had become more obvious.

The director of the National Counterterrorism Centre, Michael Leiter, said the threat posed by terrorism had been made more serious and complex because of home-grown extremists.

He said at least 63 US citizens had been charged or convicted of terrorist acts or related crimes since 2009, with groups affiliated with al-Qaeda now actively targeting Americans or Westerners who remain undetected in their own communities.